The present invention relates to an automatic camera selection system. More specifically, the present invention relates to an automatic system for video recording an auditorium type presentation, including a speaker and visual aids.
In 1994, automatic camera control software, originally designated xe2x80x9cI-See-YouTM(trademark)xe2x80x9d, now called the xe2x80x9cAutoAuditorium(trademark) Tracking Cameraxe2x80x9d, had been developed at Bellcore for automatically tracking a speaker making a presentation in an auditorium type environment. It was later realized that a computer program using some of the same software algorithms could analyze a television image of the visual aid projection screen (hereinafter called the xe2x80x9cslide imagexe2x80x9d), where a speaker shows visual aids for his or her talk. The software analysis could determine whether or not there was an interesting slide image on the projection screen (that is, the screen was not blank). Having determined that there was an interesting slide image, the program, designated xe2x80x9cI-See-You Directorxe2x80x9d, could then instruct the I-See-You camera control software to switch the tracking mode to one where the I-See-You Tracking Camera kept the moving speaker in corner mode, (e.g., the lower-left corner of the tracking camera image). Then, by using the special effects capability of a video mixer, the image of the slide and the image of the person giving the talk could be electronically mixed, thus giving a remote audience both of the images they were likely to want to see.
When the slide image was found to be blank, the I-See-You Director software could instruct the I-See-You camera control software to again switch back to the normal mode; namely, that of keeping the moving speaker in the center of the tracking camera image, and to instruct the video mixer to select the tracking camera image as the program for the remote audience.
Experiments conducted at Bellcore in February, March and April of 1994 demonstrated that two software systems, I-See-You camera control and I-See-You Director, could share the same computer hardware and perform their separate algorithms without interfering significantly with each other. Moreover, the I-See-You Director software was capable of instructing the Video Mixer to select among several video inputs at the appropriate times, and the resulting program was found to be acceptable to a human audience.
A video tape, entitled xe2x80x9cElectric Vehiclesxe2x80x94A Current Reportxe2x80x9d, Michael Bianchi, Apr. 25, 1194, was made using the I-See-You camera control software and I-See-You Director software together. The tape shows I-See-You camera control software following the speaker as he gives the talk, both in normal and corner mode, and the I-See-You Director software selecting between the special effect of speaker image and slide image together, and speaker image alone.
In order to further develop the I-See-You camera control software and the I-See-You Director software for the case of a typical auditorium talk, which is a single speaker, standing on a stage, talking to an audience, and using projected visual aids, a set of design goals was established:
a) The system should be relatively inexpensive.
b) The system should produce acceptable results, most of the time, without human intervention.
c) The system should impose few, if any, restrictions on the actions of the speaker.
Accordingly, it is an object of the present invention to provide an automatic camera control method and apparatus which achieves the aforementioned objectives.
In accordance with an illustrative embodiment of the present invention, an automatic camera selection system records an auditorium type of presentation for displaying to a remote audience. Note that the audience may be remote in terms of space or time. The displayed presentation includes composite images of a presenter and a visual aid, such as a projected slide image. The inventive system is computer controlled, and performs the following steps:
a) setting predetermined initial parameters,
b) collecting a slide image, which is a video frame obtained from a camera pointed at the visual aid, hereinafter denoted as the xe2x80x9cslide camera.xe2x80x9d The image from the slide camera is hereinafter referred to as the xe2x80x9cslide image.xe2x80x9d
c) determining a current video-noise threshold,
d) determining if there is motion in the slide image,
e) determining if the slide image is blank or not,
f) collecting a presenter image, where the presenter image is a video frame obtained from a tracking camera,
g) selecting and displaying appropriate images to the remote audience.
The displayed images of step g), above, are selected by the inventive software, in accordance with the following guidelines:
the slide image is selected when there is motion detected;
when appropriate, composite images are selected which include a combination of the presenter image and the slide image;
static or blank slide images are avoided; and
the presenter image is withheld from display while the tracking camera is being repositioned.
To implement the above described procedure, the system computer controls both a tracking camera and a slide camera, where the tracking camera is capable of viewing both the presenter and the visual aid, as well as the auditorium environment, if desired, while the slide camera is set up to view the visual aid. In addition, the video signals of the system cameras are transferred, as required, to:
a) video digitizers and buffers within the control computer for storage and image analysis,
b) a video mixer, where the video signals are selected, wither individually or in combination, for display to the remote audiences.
In addition, Video Distribution Amplifiers may be used to aid in the video signal transfers. Illustratively, the selection process is controlled by the system software, in accordance with the above described guidelines.
In addition to the tracking camera and slide camera inputs, the video mixer may also receive additional video signal inputs from other camera sources, which could be selected by the system software as well.
An illustrative embodiment of the present invention is more fully described below in conjunction with the following drawings.